The configuration of a unit cell of a fuel cell stack will be described below. A membrane electrolyte assembly (MEA) is positioned in the center of the unit cell. The MEA includes a polymer electrolyte membrane capable of transporting hydrogen ions (protons), and catalyst layers such as a cathode and an anode, which are coated on both sides of the electrolyte membrane such that hydrogen and oxygen react with each other.
Moreover, a gas diffusion layer (GDL) and a gasket are sequentially stacked on the outside of each of the cathode and the anode. A separator, in which flow fields are formed to supply and discharge a fuel (hydrogen) and an oxidant (air) and discharge water produced by a reaction, is stacked on the outside of the gas diffusion layer. An end plate for supporting and fixing the above-described components is connected to the outermost end.
The fuel cell stack, in which a plurality of the unit cells configured in the above-described manner are stacked, is mounted in a fuel cell vehicle to drive the vehicle by electricity at a desired voltage generated by the fuel cell stack.
In the fuel cell stack having the above-described configuration, as shown in FIG. 8, an end plate assembly includes an end plate 3 for maintaining a fastening force, an insulating plate 2 for preventing the electricity generated by the fuel cell stack from leaking to the outside, and a current collector 1 and current collector terminals 4 for collecting the electricity generated by the fuel cell stack and transmitting the electricity to the outside.
Moreover, in the case where a plurality of fuel cell stacks are present, a conductive busbar electrically connects the current collector terminals 4 of the end plates to connect the fuel cell stacks.
However, a connection between each of the current collector terminals 4 of the end plate 3 and the busbar is exposed to the outside and is configured as an exposed charging part. Thus, the exposed charging part may be brought into direct contact with a metallic stack enclosure due to crash, deformation, etc. of a vehicle body, thus causing an electrical short circuit, which is very problematic.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present inventive concept and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.